Monday, March 30, 2020

Dr. Peter Shields Dissects Research Tying PCBs to Lymphoma, Leading to Monsanto Trial Win

The Trial: Steele, et al v. Monsanto Co., et al., a toxic tort trial in which plaintiff claims two men developed non-Hodgkin’s lymphoma from Polychlorinated biphenyl (or PCB) used by agrochemical company Monsanto.

The Expert: Dr. Peter Shields, an oncologist at The Ohio State University, testified on behalf of the defense on research plaintiff offered in an attempt to link PCB exposure to non-Hodgkin’s lymphoma.

The Verdict: For the defense.

 By Gary F. Gansar, MD, FACS; Senior Medical Director, AMFS


In a California trial against Monsanto, Dr. Peter Shields, a medical oncologist and researcher from The Ohio State University, destroys the contention that PCBs [Polychlorinated biphenyl] used by the agrochemical giant caused two men to develop non-Hodgkin’s lymphoma when the chemicals entered the food chain. Shields’ testimony for the defense exposed important gaps in the way the research for the plaintiff had been performed and in the conclusions that it reached.

Shields concludes that the research offered by plaintiff to link PCBs to non-Hodgkin’s lymphoma violated basic scientific principles. And to make the issue easier for jurors to understand, he relates this to his own practice. What evidence, he asks, rhetorically, would be needed to state to his patients, that PCBs caused their lymphoma? The first thing that he needs in order to make this statement, is to be able to say that PCBs have caused lymphoma in anyone. Next, he tells jurors he needs a test to say that PCBs caused the lymphoma in that particular patient. However, as of the trial, Shields says, there are no validated rules that would allow him to make such a statement.

Turning directly to the plaintiff’s research, Shields says that he has never, outside of litigation, heard of the formula relied upon by plaintiff. The oncologist states plainly that comparing seven congeners of PCB [a congener being any well-defined chemical compound in the PCB category, an isomer] to a survey published by the National Center for Health Statistics, is “not an appropriate use” of this information.

Shields testifies that 90% of non-Hodgkin’s lymphomas, or NHLs, are idiopathic; in other words, their cause cannot be discerned. The other 10% of cases have a definite cause that can be pointed out, such as a bacteria, immunosuppression, or virus. In this case, plaintiff invented a method to try to determine the cause of the two men’s NHL. Shields explains however, that even if you misinterpret the data to conform to your hypothesis that PCBs can be a cause of this disease, you still have to prove that this was the cause in this particular individual.

When questioned about the methods of this formula, the doctor shows his familiarity with the researchers involved in its creation as well as their research, and he views both with skepticism. He relates the history of one National Cancer Institute researcher in particular who left the NCI to create the formula for plaintiff’s counsel as a consultant, and eventually returned to the NCI. Shields says, “I had never seen her write anything like that before… I haven’t seen anything since then, either.” He has not seen this formula anywhere else and is aware that it was created and paid for as part of a courtroom proceeding. The formula has never been tested in any scientific literature or held up to scrutiny by the scientific community. In answer to a question regarding the publication of this formula by the National Cancer Institute, the doctor retorts, “I mean, I just have not seen this anywhere.”

Shields further discusses why the conclusions reached by the plaintiff’s research are so unlikely to be accurate. Based upon the presence of any one of these seven congeners in our environment and their prevalence, Shields says 60% of the population would be at high risk for this relatively rare disorder. That makes it particularly difficult to blame a PCB isomer like this for the development of non-Hodgkin’s lymphoma in a particular patient. Indeed, as time goes on and exposure to PCBs becomes cumulative in the population as it ages, it would be well known by now that PCBs causes up to 60% of the cases of non-Hodgkin’s lymphoma based upon these figures, but that is definitely not the case. If that statistic was accurate, Shields contends, all studies involving non-Hodgkin’s lymphoma would have language in their introductory statement about PCBs being a cause of the disease, but, he says, “I’ve never seen that”.

A calm, authoritative and easily believable expert, Shields has taken apart the critical research in this case and made it unbelievable to the jury. His testimony saved Monsanto as much as $20 million when the jury ruled in favor of the defense.


Gary Gansar, MD, is residency trained and Board Certified in General Surgery. He previously served as Chief of Surgery and Staff at Elmwood Medical Center and on the Medical Executive Committee at Mercy Hospital and Touro Infirmary in New Orleans, LA. Dr. Gansar also served as Clinical Instructor and Professor of Surgery at Tulane University. He received his MD and served as Chief Resident at Tulane University Medical School. Dr. Gansar joined AMFS as a consulting medical expert in 2011 and has served as Medical Director since Nov. 2015. In this capacity, Dr. Gansar provides consultation, review and guidance to attorney clients.